Friedrich schmidt and otto ernst



UNITED STATES PATENT .FFICE.

FRIEDRICH SCHMIDT AND OTTO ERNST, OF HHOHST-ON-THE-MAIN, GER- MANY, ASSIGNORS TO THE FARBWERKE, VORMALS MEISTER, LUOIUS d5 BRHNING, OF SAME PLACE.

TRISAZO DYE.

SPECIFICATION forming part of Letters Patent No. 582,959, dated May 18, 1897.

Application filed March 5, 1897- To aZZ whom it may concern:

Be it known that we, FRIEDRICH SCHMIDT and OTTO ERNST, doctors of philosophy, citizens of the Empire of Germany, residing at Hochst-on-the-Main, Germany, have invented certain new and useful Improvements in the Manufacture of Trisazo. Dyestuffs, of which the following is a specification.

Our invention relates to the manufacture of a bluish-black trisazo dyestuif which can be developed on the fiber with considerable strength and fastness. We have found that I difficultly-soluble intermediary product is formed. Hydrochloric acid is then carefully added until the reaction of the liquid distinctly shows an acid character, whereupon a solution of 1.85 kilograms of hydrochlorid of alpha-naphthylamin is introduced. After several hours stirring the formation of the dyestuff is completed. By a careful addition of a soda solution the liquid is again made of a weak alkaline character, whereby the dyestuff, however, does not dissolve.

In a dry state the dyestuff forms a violetbrown powder of metallic luster and is soluble in water with a bluish-violet color. The color of this solution changes on addition of Benzidin (tetrazotized) Alpha naphthylamin,

forming in a dry state a violet-brown powder of metallic luster, soluble in water with a Serial No. 625,988. (Specimena) dioxynaphthalenemonosulfonic acid 1.8.4is capable of combining with two molecules of diazo compound and gives a valuable black direct-dyeing cotton dyestuff by combining one molecule of diazonaphthalenesulfonic acid with the said acid, next combining the monoazo dyestuff thus formed with one molecule of tetrazotized benzidin to a so-called intermediary product, which is capable of being further diazotized by combining it with naphthylamin or its homologues, so that a trisazo dyestuff of the combination Dioxynaphthalenemonosulfonic acid 1.8. 4 naphthionic acid (diazotized) ammonia into adull-red violet. Itis soluble in concentrated sulfuric acid with a blue color, while by addition of water a reddish-brown precipitate is obtained. The direct-dyeing color of four per cent. on unmordanted cotton is a saturated blue-black, which on be-' ing diazotized and developed on the fiber considerably increases its power of dyeing and fastness.

Having thus described our invention, we claim as new and desire to secure by Letters Patent 1. The process herein described of producing a bluish-black trisazo dyestuff, which consists in combining one molecule of diazonaphthalenesulfonic acid with one molecule of dioxynaphthalen emonosulfonicacid l .8 .4, subjecting the monoazo dyestuff thus formed to the action of one molecule of tetrazotized benzidin until a so-called intermediary product is obtained, and lastly treating the intermediary product with naphthylamin, substantially as described.

2. The new trisazo dyestuff of the combination:

Dioxynaphthalenemonosulfonic acid 1.8.4 naphthionic acid (diazotized) In testimony that We claim the foregoing as our invention we have signed our names in blue-violet color, turning to a dull-red violet presence of two subscribing witnesses. on addition of ammonia, soluble in concentrated sulfuric acid with a blue color, the diroot-dyeing color of four per cent. on unmordanted cotton being bluish black, substantially as setforth.

FRIEDRICH SCHMIDT. OTTO ERNST. Witnesses:

HEINRICH HAHN, ALFRED BRISBOIS. 

